The present invention relates to the manufacture of containers made of a material which under certain conditions exhibit superplastic properties.
It is known that certain metals for example Ti and Ti alloys exhibit the property also known as superplasticity. A superplastic material has specifically the ability to exhibit unusually high lasting elongations under tension with a commensurate reduction in cross section but without rupture. A superplastic material, therefore, has the advantage that rather complex components and shapes can be made with one single forming step. On the other hand, in the case of containers e.g. spherical containers for fuel to be used in space vehicles, it was the practice to construct such a container from half shells or semispheres and to make these through a machining process. The two semi-spheres are then bonded into a spherical tank configuration. Such a manufacture process requires complex tools, fairly expensive semi-finished products and complex clamping and position devices which have to match the various shapes and sizes and so forth. While a satisfactory product can be obtained in that fashion the manufacturing process is deemed cumbersome and therefore undesirable and subject to need for improvement.